The art has produced a variety of fan-driven devices for dispensing volatile materials into the air. Typically such devices include a housing, an air inlet and outlet with an airflow path extending therebetween, a fan to produce an airflow in the airflow path, and a variety of means for introducing the volatile materials into the airflow path. A number of these fan-driven devices utilize battery power to drive the fan.
Of particular relevance to the instant invention are such devices that utilize a replaceable cartridge or refill assembly for renewing the supply of volatile materials to be dispensed by the device. The potential always exists for incorrect placement of the refill assembly or the battery when either is changed.
The art has addressed this difficulty in various ways. For example, Corris, U.S. Pat. No. 3,990,848, utilizes a box-like container with holes in its sides. The container contains a solid, cylindrical block of a volatilizable gel. A thin, rectangular battery is mounted on top of the container, with the battery's terminals placed so as to engage electrical contacts that lead to the fan of the device. The entire cartridge, with attached gel and affixed battery, is inserted as a unit into the housing of the device so that correct placement of the container automatically provides for correct placement of the battery.
Sullivan et al., U.S. Pat. No. 4,276,236 and Tringali, U.S. Pat. No. 4,035,451, both disclose a cylindrical cartridge having a conventional, cylindrical battery held at the longitudinal axis of the cartridge, with a space between the battery and the outer wall of the cartridge holding a fluted strip of paper bearing active ingredient. The battery is integrally fastened within the cartridge.
Steiner et al., U.S. Pat. No. 4,743,406, shows an arrangement somewhat similar to Sullivan et al. and Tringali, except that the cylindrical battery is not fastened within the cartridge. Instead, the battery simply removably slips into a battery chamber designed to hold the battery with its longitudinal axis vertical. The battery chamber is open at the center of its floor so that, once a battery is placed within the chamber and the cartridge is inserted into the Steiner et al. device, spring clip terminals can engage both ends of the battery, to lead power to the fan.
Walz et al., U.S. Pat. No. 4,840,770, show a generally cylindrical cartridge that has a shallow well occupying its uppermost portion. The well is filled with a gel-like odor control product. A cylindrical battery is clipped into a slot formed in the underside of the cartridge, with the longitudinal axis of the battery oriented at right angles to the longitudinal axis of the cylindrical cartridge. Airflow impinges the cartridge only from above and does not pass through the length of the cartridge.
Holzner, Sr., U.S. Pat. No. 4,931,224, and Holzner, Sr. et al., U.S. Pat No. 5,147,582, show a generally cylinder cartridge that is reminiscent of Sullivan et al., at least in the fact that volatile material is held in an annular space that surrounds and is co-axial with a cylindrical battery. However, in the two Holzner patents, the battery is removably held within a central well, so that the battery may be removed and replaced without the need to discard the entire cartridge. In essence, the cartridge is a holder for the battery, requiring that the cartridge be in place to hold the battery within the device.
Zlotnik, U.S. Pat. No. 5,376,338, employs a ring made of a block of vaporizable material that has air passages formed within it. This ring of material is held by a sleeve that, in turn, rests upon one end of a conventional, cylindrical battery. The longitudinal axis of the battery is vertical and located within the airflow of the device. The body of the battery thus serves as a supporting structure to hold up the sleeve that in turn holds up the ring of volatilizable material. The battery can be placed in the device without the block of vaporizable material, but the cartridge cannot be held within the device without the battery.
All of these devices in which a refill cartridge of some sort is associated with a battery either are designed to provide a compact or convenient arrangement or, in some instances, to require that a battery be changed when the rest of the cartridge is changed, renewing simultaneously both the electrical source and the source of volatile material to be dispensed by the device. However, none of this art presents an arrangement in which an air transmitting substrate bearing a volatile active ingredient is held by a refill assembly that is used in association with but remains separate from the battery such that successful placement of the battery within the device requires that the refill assembly have been correctly installed so that the substrate is held within an airflow through the device, with the further advantage of placement of the battery in a non-obstructing position with respect to the airflow.
An important problem for a user of a battery-powered, fan-driven device to dispense a volatile material is detecting or predicting when either the battery or the volatile material is or will be depleted. This especially can be important when the volatile is an insect control agent used in a sleeping room, for example, so that a dead battery or depleted volatile may mean an irritating midnight mosquito attack, with the attendant risk of mosquito-borne disease, in some locales.
The art is aware of the use in these devices of various control mechanisms that provide use-up indicators or timing circuits to measure the use or indicate the depletion of either the battery or the volatile material being dispensed. For example, Muderlak et al., U.S. Pat. No. 4,830,791, shows a timing circuit that provides a visual indication that a set number of days have passed since operation of the device was initiated or a reset switch was last pressed. The volatile material used in Muderlak lasts about 30 days, so the device is set to give a visual indication of the passage of time at 32 days. The timer operates by generating electrical pulses at set time intervals. A counter generates a latch signal when it has received a predetermined number of pulses.
Walz et al. does not include a timer or indicator device but does utilize an amount of a gel-like odor control product selected to be sufficient that battery life and the life of the volatile ingredient are about the same. As a consequence, the "product and battery can be installed and replaced at the same time as a unit, thus assuring that an old battery is not left in by mistake." (Column 7 at Lines 49-52).
The Tringali cartridge, also shown in Sullivan et al., permanently mounts the battery within the same cartridge that carries the device's supply of volatile ingredient. Although no use-up indicator is supplied, at least the battery and volatile material must of necessity be replaced at the same time.
Muderlak et al., U.S. Pat. No. 5,175,791 uses a timer circuit to step up power over time to the heater utilized to cause the active ingredient to be dispensed. The Muderlak et al. '791 device is not battery driven, does not utilize a fan, and is noted only for its general use of a timer circuit.
Kunze, U.S. Pat. No. 5,370,829, discloses timed operation of the battery-driven fan of the device. However, the timer appears not to be designed to measure consumption of either battery power or volatile ingredient.
To be flexible in use, it is valuable that a device of the sort being discussed be capable of assuming more than one orientation, to allow the airflow coming from the device to be directed toward a desired part of the airspace of a room, for example, from different locations about the room. The presence of a heavy battery within the housing of an otherwise light-weight device can present some difficulties in accomplishing this.
A few of the devices shown in the art provide for more than one orientation of the device. Thus, the device shown in Baker et al., U.S. Pat. No. 4,666,638 is designed to either be wall mounted or supported by a flat surface. An anti-roll chamfered segment is formed in the housing of the Baker et al. device to allow it to sit
stably on a flat surface, with the air discharged from the device angled upwardly. When the same device is mounted on a wall, it is securely fastened to the wall with the airflow directed horizontally, outwardly from the wall.
The device shown in Chien, U.S. Pat. No. 5,168,654, utilizes a clip leg to achieve two different orientations on a flat surface. In the first orientation, the clip leg is folded flat against the housing of the device, and the airflow is projected directly upwardly from the device. In the second position, the clip leg is opened to brace the device upwardly from the flat surface at an angle. The Chien device utilizes a heater to dispense an active ingredient from a solid repellent and is not battery operated.
Various other devices exist in the art, and those referred to, above, are by way of example only. The art is still in need of a device that provides an easy means for a user to detect when a replaceable substrate bearing an active ingredient has been improperly inserted into the device. Similarly, the art still is need of an elegant design that allows a user to control the direction of airflow from a battery powered blower device, as well as such a device that signals the user when battery power is about to or has become insufficient for effective use of the device. All of these features are important to a practical and useful battery operated device for dispensing a volatile active ingredient into the air.